1. Field of the Invention
This invention relates to a debris collection apparatus and, more particularly, to a vacuum type filtration and collection system which can collect both wet and dry debris.
2. Description of the Prior Art
Vacuum debris collecting devices are well known in the art. These devices typically include a main receptacle for storing the collected debris, a vacuum pump or the like for creating a vacuum in the receptacle, and an intake hose for drawing the debris into the receptacle. Most vacuum devices rely on gravity as a primary means for separating the debris, but other devices rely additionally on cyclone filters, bag filters, and the like for separating particulate matter of varying sizes from the collected debris.
Vacuum debris collection systems are often mounted on vehicles and are used for collecting debris from a wide range of sources, including mines, power plants, grain storage vessels, industrial plants, sewers, and the like. Such locations present a wide variety of debris to be collected, ranging from small, fine dust particles, to larger particles, to liquid debris, and to a combination of all types. Normally a vacuum vehicle is driven to a pickup site where the debris is drawn into the storage receptacle. The vehicle is then driven to a dump site where the contents of the receptacle are removed.
Many locations generating debris do not require cleanup on a daily basis. For this reason, it is common for vacuum vehicles to travel from one site to another, either on subsequent days or within the same day. Since some of the known vacuum vehicles are not particularly suited for collecting one type of debris or another, such as fine, dry particulate matter or liquid material, it is necessary that a suitable vehicle be dispatched to the location in accordance with the debris to be collected It is also known to provide a vacuum truck with multiple capacities which can be selected for the debris to be collected. For example, a control switch can be activated to configure the vacuum vehicle appropriate to collect dry debris or wet debris.
The prior art known to applicant in this area includes the following U.S. Pat. Nos. 3,052,908; 3,193,867; 3,404,776; 3,406,423; 3,535,851; 3,842,461; 3,870,489; 3,885,932; 3,973,935; 4,062,664; 4,134,174; 4,162,149; 4,218,226; 4,227,893; 4,283,205; 4,509,963; 4,574,420; 4,578,840; 4,909,814; 4,935,984; and 4,946,483.
One of the problems with the prior art vacuum systems is that a decision may need to be made on the mode of operation for the system depending on the type of debris to be collected. If the wrong choice is made, such as selecting the dry mode when wet debris is collected, certain parts of the system may be damaged. This is a particular concern when bag filters are used in the system and moisture laden debris contacts the bags. The bags can either be clogged to a point where they cannot be used until they dry out, or the bags could become ruined. In addition, the use of a control switch forces the operator to make a decision each time debris is to be collected. Finally, regardless of the mode selected, the nature of the debris may unexpectedly change while it is being collected, resulting in damage to the system.
Therefore, it is an object of the present invention to provide a vacuum system which can collect both wet and dry debris in a single mode of operation. It is another object of this invention to provide such a vacuum system in an arrangement which prevents moisture from reaching a series of bag filters. Furthermore, it is an object of the present invention to provide a vacuum system which has improved debris separation abilities so that only dry, fine particles remain in the air stream when it reaches the bag filters.